P0469: EVAP Purge Flow Sensor Circuit Intermittent

What does P0469 mean?

The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. A purge flow sensor – a heated thermistor in the purge line between purge valve and intake manifold, as described in a Ford patent – measures purge flow directly for the CARB purge monitor. Today indirect methods (fuel trim, tank vacuum) have largely replaced it; no manufacturer document available to us uses these codes. P0469 means the signal jumps or drops out briefly, usually from a loose contact. The purge flow monitor can then not be evaluated.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• EVAP readiness not set, emission inspection not passed
• No change in driving

Common causes

• High Loose contact at the connector
• Medium Wire broken by engine movement
• Low Sensor faulty internally

Likelihood is a general estimate across vehicles; your make and model may differ.